Electromagnetic field generator



Dec. 8, 19.31. F, M HENRY 1,835,870

ELECTROMAGNETIC FIELD GENERATOR Filed April l2, 1950 INVENT UR HTTRNEPatented Dec. 8, 1931 PATENT or-Flc FRANKLIN M. HENRY, F SAN FRANCISCO,CALIFORNIA ELECTROMAGNETIC FIELD GENERATOR Application med April 12,1930. Serial No. 443,793.

My invention relates to ap aratus for producing electromagnetic fiel sand particularly alternating electromagnetic fields adapted fortherapeutic use, and which aty the same time may. have many uses otherthan said therapeutic uses.

One object of my improvement is the provision of a simple andv efficientdevice of the character mentioned.

Another object is the provision of a core and coil construction whichwill give a maximum strength of field at a particular point with aminimum temperature change in operation.

Another object is the provision of a device of this character having amaximum strength of field with a minimum weight and size.

Another object is the provision of means whereby major portions of themagnetic flux 20 from the core may be concentrated in desired portionsof the pole piece.

A further object is the provision of means for compensating forcontractions and expansions of parts of a device of the charactermentioned.

A still further object is the provision of a novel means for connectingan electrical power supply to a coil of the character referred to.

Other objects and advantages will be apparent during the course of thefollowing def scription.

In the accompanying drawings forming a part of this specification and inwhich like 5 numerals are employed to designate like parts throughoutthe same,

Figure 1 is a diagrammatic view of the core andv electrical circuitarrangement embodying one form of my invention.

Figure 2 is a vertical cross section of one form of my device, anddiagrammatcally illustrating the wiring arrangement.

Figure 3 is a top plan view of Figure 2.

Figure 4 is a fragmentary sectional view of the spool end.

Figure 5 is a horizontal cross section on line 5-5 of Figure 2.

Figure 6 is a horizontal cross section taken r on line 6 6 of Figure 2,and

Figure 7 is a fragmentary side elevation of the lower end portion of mdevice.

In the accompanying rawings wherein for the purpose of illustration isshown a prey fer-red embodiment of my invention, there is shown a layerwound coil 5 properly insulated from and disposed on a suitable corewith an exposed pole piece at one end, said pole piece servin tofacilitate directing an electromagnetic eld to a desired position foruse.

Y I preferably `provide a laminated core madeup of elongated sheets 10as illustrated, or in any conventional manner. Each lamination 10 isprovided with a portion 11 disposed at an angle to the part 10 andadjacent a pole piece 12. An important feature of my improvement is thedisposition of the core lamination parts 1l with respect to the poleiece 12. The parts 1l may be bent Ysharp y and arranged substantiallyparallel to the adjacent surface of pole piece 12, or bent at a greaterangle to the parts 1() and engage the pole piece 12 nearer the lateraledges of the latter. The core laminations are illustrated with theportions 11 of the laminations divided into two groups and directed inopposite directions, but these parts 11 may be divided into as manygroups as may be desired and disposed in as many directions.

The parts 11 serve as means for directing major portions of the fluxfrom the core to desired portions of the pole piece. When the parts 11are bent sharply with little space .13 at the center of the core, as inFigure 2, the flux will be directed more strongly toward the centralportion of the pole piece 12 and when the parts 1l are disposed lessacutely the parts 11 facilitate directing most of the f* flux to edgeportions of the pole piece 12,

see Figure l.

The portions 11 of the core may be secured vto the pole piece 12 in anydesired manner.

.I have illustrated in Figure 7 convenient Vmeans by providing twoscrews 14 which extend through an adjacent spool end 15 and threadedinto pole piece 12 so that the parts l1 are held firmly against polepiece 12.

The spool upon which the wire coil is mounted may be formed in anydesirable manner, but I prefer to make this spool np of two end pieces15 and 16 with a tubular member 17 joining the two spool ends. The ends15 and is of an insulating material, such asvulcanized fibre, or thelike. On this spool-islwound winding may be arranged in the ConventionalVor any desired manner to provide means for i producing theelectromagnetic luXY in the core when an electric current is conductedthrough the wire of the coil. This coil is designated by the numeral 19and it isdiagrammatically shown in the drawing. At the end of the spool15 whichis adjacent pole piece 12,1 preferably provide a thin insulationdisc 2O to insure electrical insulation between the lend of the coil 19Vand the Yheads of screws 14.

The spool end 16 isthreaded to receive two yscrews 21, which passthrough a block 22 with the heads of screws 21 countersunk into block 22as-clearly illustrated in Figures 2 and 5.

This provides a means for securing block `22 to spool end 16. 'A block23 of ldisc form rests against block 22 and is held securely thereto bytwo screws 24. f The screws 24 also pass throughportions of theconnectormemployed wherever it is desired for the purpose of givingtherapeutic treatment.

It is to be understood that the form of my invention herewith shown and-described isto be taken as a preferred example of the same and thatvarious changes relative to the material, size, shape, `and arrangementof parts may be resortedto without departing from the spirit of theinvention or the scope ofthe sub'oined claim. a plurality of layersofinsulated wire. VThis Y aving thus far described my invention, I claimln a devicepofthe character mentioned, a spool having cylindrical ends,a block secured v.tol'saidspooleend and narrower inone direction thansaid spool, a-blocl ot substantially f the diameter of said spoolendsecured to the iirst mentioned block, there being openings in said spoolend and block, and a coil of wire on saidspool with end portionsvdisposed in jacent edges of the rst mentioned block disposed in loops.

in testimony whereof I ailiX my siffnature.

"bers 25. The connector members 25 Varev prefi 'erably set ina recess 26so thatthe bend in portions thereof and the heads orF screws 24 VareVbelow the outer surface of number 23.

Perforations 27 are-provided through thev spool end 16 and disc 23 toconduct the ends ofthe-wire in coil 19 out to the connector by means ofscrews 28. The members 25 are adapted to connect with connector plugs,proi curable in the open market andrnot illustrated. i

' The block 22 is of discV form except for cut away portions at oppositesides, providing recesses 22in whichvend'portions19 of the wire of coil'19 are disposed in loopsso ,that if a wire end becomes broken at ascrew 128 some of portion 19 may be pulled outand secured under thescrew 28 again.

' I provide a resilient covering 29 around the coil` V19 and insidev ofatubular casingl which surrounds all the rparts except Apole ypiece 12.This covering prevents the parts" from becoming noisy` due to expansionsand -cross section to till the 'space between the coil 19 and casing 31in the manner described. l

The tubular-covering 31 surroundsthe coil covering 29. and has one ofits ends abutting `pole piece 12. The oppositeend Yof covering 5 31 issecured to disc' 23 `as by screws 32.

.' This completes the unit which maybe em- 'i i' Y v, e5 said openingswith portions of the wire ad

